The invention relates to a compound machine for producing a staple fiber yarn, including an air spinning machine for prespinning the yarn. The spinning points of this air spinning machine each contain a drafting frame, a pneumatic false-twisting nozzle, a withdrawal device and a wind-up device for winding up a spool with prespun yarn. The yarn is subsequently finish-spun on further devices of the combination machine, the spinning points of which further devices each contain at least one spool receiving device and a ring spindle.
It is known from Japanese Patent (JP-PS) No. 60-15 729 B to pneumatically prespin a yarn by means of an air spinning machine to which the fiber material is fed in roving bobbins and then to wind the yarn onto spools that are subsequently fed to a simplified ring spinning machine and are finish-spun there. The ring spinning machine is simplified to such an extent that, instead of drafting frames for the spinning points, in each case, only spool receiving devices are provided. It is possible, by means of this type of yarn production, to increase production speed since, on the one hand, in the area of the air spinning machine, work can take place at very high speeds. On the other hand, it is Possible, by means of the ring spinning machine, to also operate at significantly higher speeds since the .alpha.-value or so-called twist coefficient, in comparison to ring yarn spun in the conventional way, can be reduced by 30% to 50%.
In the case of a known arrangement of European Patent Application (EP-A) No. 38 143, on a first machine, two drawn and prestrengthened slivers are wound onto a feed spool as a double yarn. Neither the prestrengthened slivers, nor the double yarn can be used as a yarn in this form because their strength is insufficient. The individual yarn components, particularly by means of pneumatic false-twisting, are prestrengthened only to such an extent that they withstand the strains occurring during the winding-up of the double yarn on the feed spool. In this case, individual marginal fibers are wound around the essentially untwisted yarn core. The actual strength of the yarn structure is generated only in a subsequent twisting process that takes place on a machine used for twisting to which the feed spools with the double yarn are fed. The efficiency of this process is mainly based on the fact that the two prestrengthened yarn components do not receive a permanent spinning twist, so that consequently this spinning twist does not have to be undone in the subsequent twisting process. As a result, the production performances can be increased of the machine for the generating of the feed spool as well as of the machine used for twisting. If the whole operational sequence were carried out in one machine; i.e., if the two prestrengthened yarn components, instead of being wound onto a feed spool, were fed to a twisting device, the efficiency would be impaired because the speeds of the two operating steps are not in harmony with one another.
An objective of the invention is to provide an arrangement of the initially mentioned type that utilizes the advantages of both types of machines in a way that is as economical as possible.
This objective is achieved by connecting an air spinning machine and ring spinning machine, by means of a conveying device for the spools receiving the prespun yarn, to form a combination machine system or compound machine, the ring spinning machine portion and the air spinning machine portion of this machine system each having a mutually coordinated number of spinning points.
A machine system or compound machine of this type permits an economical method of operation because the spinning points of the faster air spinning machine portion, with respect to their number, are coordinated with the slower spinning points of the simplified ring spinning machine portion. However, each of the two machine portions can be utilized fully and therefore operate economically.
A machine system or compound machine of this type may be generally compared approximately with the combination of a flyer and a ring spinning machine that is customary in the case of the classical ring spinning method, according to certain aspects of the inventive compound machine. In this case, the air spinning machine portion takes over a function like the flyer, already at this point containing the drafting frames of the classical ring spinning machine. The air spinning machine portion can operate at very high speeds, one spinning point taking over the drafting frame work of about 20 spinning points of the current ring spinning machine. By means of the reduction of the number of drafting frames, the servicing and the cleaning of high-performance drafting frames of this type can be simplified, because the surfaces to be cleaned are reduced considerably. The manufacturing of the simplified ring spinning machine, because of the absence of the drafting frame, is about 35% less expensive than that of a classical ring spinning machine. In addition, as a result of the increase of the operating speeds, the number of the required spinning Points is clearly reduced, resulting in a further reduction of cost.
Furthermore, the simplified ring spinning machine portion of the present invention leads to higher efficiency because the number of yarn breakages is reduced. Since the prespun yarn has an increased strength compared to a normal sliver, yarn breakages are relatively infrequent in the simplified ring spinning machine. Also in the air spinning machine portion, the danger of yarn breakages is relatively low because no balloon of yarn is required in its area, the effect of which goes back to the delivery cylinders of the drafting frame. In addition, the servicing can be simplified because one operator, who is still required even for an automatic operation, can take care jointly of both connected machine portions, having to cover only very short distances. In addition, because of the high performance of the inventive compound machine, relatively short overall machines are obtained so that the space requirement is reduced for given volume of yarn production.
The economic advantage in comparison to the combination of a flyer and a ring spinning machine can also be clearly demonstrated by means of a numerical example. If a yarn of a count of Nm50 is to be spun at 1,000 spinning points of a conventional ring spinning machine, about 30 operating points of a flyer are assigned to them. In the case of the same production and the same yarn count, the machine system or compound machine of the invention requires only 73 spinning points for the air spinning machine portion and about 700 spinning points for the simplified ring spinning machine portion. The resulting advantage becomes even clearer if finer yarn counts are to be spun. In the case of the machine system according to the invention, the air consumption becomes continuously less in the case of finer yarn counts, while, nevertheless, also in the case of fine yarn counts, the work in the area of the air spinning machine can take place at very high delivery speeds, because no balloon of yarn exists there that strains the yarn.
In especially preferred embodiment of the invention, the designing of the compound machine system for the practical operation takes place in such a way that the number of spinning points of the air spinning machine portion and of the ring spinning machine portion is determined for the finest yarn count that is contemplated to be processed in this special operation. When coarser yarn counts are spun, if necessary, spinning points of the simplified ring spinning machine portion will then not be used. If two prestrengthened yarn components at each spinning point are fed to the machine portion for the finish-spinning, which, as a rule, is a simplified ring spinning machine, a twisted-yarn-type staple fiber yarn is produced. In this case, it is contemplated in certain preferred embodiments to feed the yarn component of two spools, or to carry out the feeding from only one feeding spool on which two yarns are wound as a double yarn. In this case, the machine portion for the finish-spinning may be a double-twist frame.
Other objects advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.